1. Field of the Invention
The present invention relates to a control system for controlling a continuous rubber molding apparatus including: a feed portion for feeding a rubber material already removed of foreign substances or particles in the previous step: an extruder for kneading and feeding forward the rubber material fed thereto; and a gear pump for delivering the rubber material, fed from the extruder, to a forming nozzle.
2. Background Art
The continuous rubber molding apparatus generally takes the following procedure for rubber molding. The procedure includes the steps of: feeding a rubber material via a feed port; kneading and extruding the fed rubber material by means of a screw of the extruder; removing foreign substances or particles from the extruded rubber material by passing the material through a strainer; delivering a constant amount of rubber material, which is removed of the foreign substances or particles, to a forming nozzle by means of a gear pump; and continuously extruding a rubber ribbon of a predetermined sectional shape from the forming nozzle. The rubber ribbon is sequentially wound on an outer periphery face of a tire-building drum, thereby forming a rubber layer of a tire. Such a continuous rubber molding apparatus is known to the art, such as one disclosed in JP-2001-30338A, for example.
For size reduction of the continuous rubber molding apparatus, there may be contemplated an arrangement wherein the screw of the extruder is shortened. An advantage of downsizing the continuous rubber molding apparatus is that the rubber ribbon extruded from the continuous rubber molding apparatus can be directly supplied to a tire-building drum. In order to wind the rubber ribbon on the tire-building drum, the rubber ribbon must be moved along an axial direction of a shaft of the tire-building drum. If, in this case, the continuous rubber molding apparatus can be downsized, the continuous rubber molding apparatus itself may be moved in a manner that the rubber ribbon may be directly and sequentially wound on an outer periphery face of the tire-building drum. Hence, the screw may be shortened to downsize the continuous rubber molding apparatus, as described above, thereby accomplishing the size reduction of the continuous rubber molding apparatus.
However, the following problem is encountered where the screw is shortened. The shortened screw entails varied outputs of the rubber ribbon extruded from a forming nozzle so that the rubber ribbon cannot be formed in a desired shape. This is because the rubber material to be kneaded is varied in viscosity so as to cause variations of pressure in the gear pump.
In view of the foregoing, it is intended to provide a control system for continuous rubber molding apparatus; the system ensuring a consistent output of a rubber ribbon from the apparatus even if the apparatus is downsized by shortening a screw.